The Hidden Price Tag: How Development Codes & Restrictive Zoning Inflate Project Costs Before Ground is Broken-Part 2

In Part 1, we talked about how detention requirements are not driven only by what jurisdictions you are in. The site itself, its drainage pattern, outfall options, and physical limitations can quickly force a detention design that is far larger (and more expensive) than expected.

In this Part 2 extension, I want to focus on what I am seeing more often on larger tracts across Brazoria.

County and surrounding areas:

✅ Sites that “drain the wrong way”

✅ New policies tightening downstream assumptions

✅ TXDOT outfall limitations that force oversized ponds

✅ Roadway impact fees that stop projects before they start

Sometimes the biggest problem is not engineering the detention pond. It could be a situation where you cannot discharge where you need to, and you cannot afford what is required to build what is left.

1. When the Site Drains Wrong

Most developers expect detention. What surprises people is when the project pencils out until you learn:

•  Your only reasonable outfall is a roadway ditch.

•  The natural flow direction does not match that outfall.

•  or pumping is required (and pumping is heavily restricted)

More jurisdictions are focusing on natural drainage pathways and limiting discharge that looks like “new drainage” being pushed to a system that did not historically receive it. So even if you can physically connect to an outfall you may not be allowed to legally connect to it.

That is where engineering turns into a policy problem.

2. TXDOT Outfall Restrictions: The Hidden Project Killer

For many large tracts, the closest outfall is a TXDOT roadway ditch. However, TXDOT does not accept outfall just because it is nearby. A major factor is whether the property naturally drained to TXDOT ROW historically. If it did not, TXDOT can deny discharge outright, and if you have no other drainage alternative, the project can fall apart immediately.

Pumping may be allowed but the restrictions can force bigger ponds.

TXDOT may allow a pumping solution in certain cases (commonly with 75% gravity capability), but the real issue is releasing restrictions especially on pumped systems.

If discharge is limited (even down to a fraction of what you would normally be allowed), detention cannot empty efficiently.

And if the jurisdiction also has a required maximum drain time, your options disappear fast:

•  You cannot drain slow forever.

•  You cannot exceed the restricted release rate.

•  Pumping does not solve the drain time requirement.

•  so, the only lever left is… more storage volume.

That is how a detention pond becomes dramatically larger than expected and that is often the moment project profitability disappears.

3. Manvel: Outfall Reality + Strict Pumping Parameters

Manvel continues to see rapid growth, especially on larger tracts. But projects cannot rely on “standard detention planning” anymore as policies evolve to address:

•  cumulative downstream impacts

•  outfall capacity concerns

•  master drainage alignment

•  preservation of natural drainage corridors

Manvel does allow pumped systems, but the requirements are so strict it often feels like pumped ponds are not truly viable. One key restriction is that a pumped pond cannot be located within 1,000 feet of a residential home, which eliminates pumping entirely for many sites near existing neighborhoods. Bottom line: the closest outfall is not always an acceptable outfall, and the most “convenient” drainage path is not always a permitted one.

4. The Silent Freeze: Roadway Impact Fees Are Pausing Projects

Even after a drainage plan is solved, more projects are still getting stuck because of a separate issue:

Roadway impact fees and offsite improvement obligations

These fees are increasingly reaching levels that pause projects at the planning stage not because developers do not want to build, but because the numbers simply do not pencil out.

Impact fees are commonly tied to:

•  trip generation

•  corridor widening requirements.

•  TxDOT or city roadway upgrades

•  intersection improvements and signalization

And this creates a new form of project failure:

✅ the site is technically developable

❌ but the cost stacking kills it before construction

Mont Belvieu Example: “Per Vehicle-Mile” Fees Can Add Up Fast

Mont Belvieu provides a clear example of how roadway impact fees can hit six figures or seven figures quickly.

The City’s Roadway Impact Fee Update shows service area rates of:

•  $1,258 per vehicle mile (West Service Area)

•  $1,757 per vehicle-mile (East Service Area)

Using ITE-based vehicle-mile factors from the same report, a 50,000 SF project can generate roadway

Impact fees like:

•  Shopping Center (ITE 820): ~$228K (West) / ~$319K (East)

•  General Office (ITE 710): ~$426K (West) / ~$595K (East)

•  Supermarket (ITE 850): ~$541K (West) / ~$756K (East)

•  Medical-Dental Office (ITE 720): ~$1.05M (West) / ~$1.46M (East)

•  Fast Food w/ Drive-Thru (ITE 934): ~$1.37M (West) / ~$1.91M (East)

So even if drainage can be solved, roadway fees alone can stop a project before it ever reaches permitting. Roadway impact fees are becoming a trend that cities are adopting to help pay for their CIP projects.

5. The Lesson: Outfall Strategy Must Be a Due Diligence Priority

If there is one takeaway from this, it is this:

✅ Outfall assumptions should never be based on proximity alone.

Before buying a tract or finalizing design teams need answers early:

•  Where did the property naturally drain before development?

•  Is the receiving ditch public, private, or TXDOT controlled?

•  Does TXDOT accept outfall, and under what conditions?

•  Will pumping be required, and will restrictions force larger detention?

•  Is there a maximum drain time requirement?

•  Are roadway impact fees known early enough to evaluate feasibility?

A “cheap” tract with a bad outfall is not a deal.

One of the biggest mistakes I see is waiting until after land is under contract, or after layout is complete before bringing in the civil engineering team. By that point, many of the biggest cost drivers are already locked in.

When your site drains the “wrong” direction, when TXDOT outfall restrictions apply, or when a jurisdiction tightens pump system parameters, the cost increases are not small; they can change the entire feasibility of the project. Add roadway impact fees on top of that, and a project that looked like a win can become financially unworkable overnight.

Bringing your civil engineering team in early helps identify real outfall options, realistic detention footprints, and the true cost of offsite requirements before the project is committed. In today’s development climate, early civil due diligence is not an extra step, it is the difference between a project that moves forward and one that dies in the feasibility meeting.

Disclaimer: This article is intended for general information only and does not provide engineering advice. Always consult a licensed professional engineer for project-specific guidance.

By Jennifer Henrichs | JRH Engineering & Environmental Services, Inc.January 2026